This application is to continue study of the developmental consequences of prolonged social isolation and psychosocial deprivation in an adolescent girl, who for most of her life was confined to a closed room where she was harnessed into a seated posture. For approximately two years this girl has been the subject of careful study to determine the degree to which a comprehensive program of rehabilitation can trascend the distorting effects of early experience. Human development, especially the concept of critical periods in development are being studied through 1) documentation on natural behavior; 2) psychological testing; 3) and records of linguistic behavior including syntactic analysis, acoustic analysis and dichotic listening tests and 4) reconstruction of the developmental history and familial antecedents that were associated with the isolation. Of particular interest in the study of this subject is the development of lateralization of function in both with respect to linguistic and non-linguistic behavior. Since emergence from isolation the subject has demonstrated significant developmental improvement.